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<table width="100%" summary="page for mgus"><tr><td>mgus</td><td style="text-align: right;">R Documentation</td></tr></table>

<h2>Monoclonal gammopathy data</h2>

<h3>Description</h3>

<p>Natural history of 241 subjects with monoclonal gammopathy of
undetermined significance (MGUS).
</p>


<h3>Usage</h3>

<pre>
mgus
mgus1
</pre>


<h3>Format</h3>

<p>mgus: A data frame with 241 observations on the following 12 variables.
</p>

<table summary="Rd table">
<tr>
 <td style="text-align: left;">
    id:</td><td style="text-align: left;"> subject id </td>
</tr>
<tr>
 <td style="text-align: left;">
    age:</td><td style="text-align: left;"> age in years at the detection of MGUS </td>
</tr>
<tr>
 <td style="text-align: left;">
    sex:</td><td style="text-align: left;"> <code>male</code> or <code>female</code> </td>
</tr>
<tr>
 <td style="text-align: left;">
    dxyr:</td><td style="text-align: left;"> year of diagnosis </td>
</tr>
<tr>
 <td style="text-align: left;">
    pcdx:</td><td style="text-align: left;"> for subjects who progress to a plasma cell malignancy </td>
</tr>
<tr>
 <td style="text-align: left;">
       </td><td style="text-align: left;"> the subtype of malignancy: multiple myeloma (MM) is the </td>
</tr>
<tr>
 <td style="text-align: left;">
       </td><td style="text-align: left;"> most common, followed by amyloidosis (AM), macroglobulinemia (MA),</td>
</tr>
<tr>
 <td style="text-align: left;">
      </td><td style="text-align: left;"> and other lymphprolifative disorders (LP) </td>
</tr>
<tr>
 <td style="text-align: left;">
    pctime:</td><td style="text-align: left;"> days from MGUS until diagnosis of a plasma cell malignancy </td>
</tr>
<tr>
 <td style="text-align: left;">
    futime:</td><td style="text-align: left;"> days from diagnosis to last follow-up </td>
</tr>
<tr>
 <td style="text-align: left;">
    death:</td><td style="text-align: left;"> 1= follow-up is until death </td>
</tr>
<tr>
 <td style="text-align: left;">
    alb:</td><td style="text-align: left;"> albumin level at MGUS diagnosis </td>
</tr>
<tr>
 <td style="text-align: left;">
    creat:</td><td style="text-align: left;"> creatinine at MGUS diagnosis </td>
</tr>
<tr>
 <td style="text-align: left;">
    hgb:</td><td style="text-align: left;"> hemoglobin at MGUS diagnosis </td>
</tr>
<tr>
 <td style="text-align: left;">
    mspike:</td><td style="text-align: left;"> size of the monoclonal protein spike at diagnosis </td>
</tr>
<tr>
 <td style="text-align: left;">
    </td>
</tr>

</table>

<p>mgus1: The same data set in start,stop format. Contains the id, age, sex, and
laboratory variable described above along with
</p>

<table summary="Rd table">
<tr>
 <td style="text-align: left;"> 
    start, stop:</td><td style="text-align: left;"> sequential intervals of time for each
      subject </td>
</tr>
<tr>
 <td style="text-align: left;">
    status:</td><td style="text-align: left;"> =1 if the interval ends in an event </td>
</tr>
<tr>
 <td style="text-align: left;">
    event:</td><td style="text-align: left;"> a factor containing the event type: censor, death, or plasma cell malignancy </td>
</tr>
<tr>
 <td style="text-align: left;">
    enum: </td><td style="text-align: left;"> event number for each subject: 1 or 2
  </td>
</tr>

</table>



<h3>Details</h3>

<p>Plasma cells are responsible for manufacturing immunoglobulins, an
important part of the immune defense. At any given time there are
estimated to be about <i>10^6</i> different immunoglobulins in the circulation
at any one time.  When a patient has a plasma cell malignancy the
distribution will become dominated by a single isotype, the product of
the malignant clone, visible as a spike on a serum protein
electrophoresis. Monoclonal gammopathy of undertermined significance
(MGUS) is the presence of such a spike, but in a patient with no
evidence of overt malignancy.  This data set of 241 sequential subjects
at Mayo Clinic was the groundbreaking study defining the natural history
of such subjects.
Due to the diligence of the principle investigator 0 subjects have
been lost to follow-up.
</p>
<p>Three subjects had MGUS detected on the day of death.  In data set
<code>mgus1</code> these subjects have the time to MGUS coded as .5 day before
the death in order to avoid tied times.
</p>
<p>These data sets were updated in Jan 2015 to correct some small errors.
</p>


<h3>Source</h3>

<p>Mayo Clinic data courtesy of Dr. Robert Kyle.
</p>


<h3>References</h3>

<p>R Kyle, Benign monoclonal gammopathy &ndash; after 20 to 35 years of
follow-up,
Mayo Clinic Proc 1993; 68:26-36. 
</p>


<h3>Examples</h3>

<pre>
# Create the competing risk curves for time to first of death or PCM
sfit &lt;- survfit(Surv(start, stop, event) ~ sex, mgus1, id=id,
                subset=(enum==1))
print(sfit)  # the order of printout is the order in which they plot

plot(sfit, xscale=365.25, lty=c(2,1,2,1), col=c(1,1,2,2),
     xlab="Years after MGUS detection", ylab="Proportion")
legend(0, .8, c("Death/male", "Death/female", "PCM/male", "PCM/female"),
       lty=c(1,1,2,2), col=c(2,1,2,1), bty='n')

title("Curves for the first of plasma cell malignancy or death")
# The plot shows that males have a higher death rate than females (no
# surprise) but their rates of conversion to PCM are essentially the same.
</pre>


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